Reading from Exodus Chapter 23
After giving the commandments to keep the Three Pilgrimage Festivals of Pesach (15-21/1), Shavuot (3/6) and Sukkot (15-21/7), in verses 14 to 19, the LORD commanded Israel to obey His Angel (often called the Angel of the LORD), who will bring them into the promised land, because "My Name is on him", says the LORD.
This is often described as the Agency of God by some, where the presence of the Angel of the LORD is to be regarded as the presence of the LORD himself.
Visit this link for a more detailed commentary:
https://onegodworship.com/the-principle-of-agency-in-the-old-testament/
Exodus 23:20 - 21 LXX
20 And, behold, I send my angel before thy face, that he may keep thee in the
way, that he may bring thee into the land which I have prepared for thee.
21 Take heed to thyself and hearken to him, and disobey him not; for he will
not give way to thee, *for my name is on him*
